The HD is a pup I've been watching increasingly closely, generally through the lens of Antag's clips. I've got a Charvel Charvette that it might sit nicely in. I would think the HD would be a bit more versatile, though still very "metal" and powerful, while the Warpig would bring a bit more brutal power (albeit warmed with alnico goodness) to the board. I don't know enough to say anything more useful than that, though, not having compared the HD and Warpig clips directly (or played through them)!